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25 Functions in a 25-Cent Micro

Small microcontrollers are often used to provide standard functions like a UART-to-UART bridge. Developing an application from scratch isn’t hard, but why do it again after it has been done before?

1. The MSP430FR2100 is the top end of the family. It adds the 8-channel, 10-bit SAR ADC with 1.5-V reference and temperature sensor.

That’s where Texas Instruments’ (TI) latest MSP430FR2000 family (Fig. 1) comes in. These devices are designed for low-cost applications, starting at just 25 cents in quantity. TI also delivers 25 applications that can be customized, thereby reducing time-to-market. They include:

Timer functions

External RTC with backup memory

7-segment LED stopwatch

External programmable watchdog timer

Programmable system wakeup controller

Simple RTC -based system wakeup controller

Voltage monitor with a time stamp

Pulse-width-modulation functions

Analog input to PWM output

Dual-output 8-bit PWM DAC

Servo-motor control

Stepper-motor control

UART software-controlled RGB LED color mixing

System functions

ADC wake and transmit on threshold

EEPROM emulation

Low-power hex keypad

Quadrature encoder position counter

Hysteresis comparator with UART

Multifunction reset controller

Single-slope analog-to-digital conversion technique

Tamper detection

Programmable clock source

Programmable frequency-locked loop

Communication functions

Single-wire communication

SPI IO expander

UART-to-UART bridge

UART-to-SPI bridge

These are often available as app notes, but tend to be more complete. They’re also designed to be customized. They take advantage of the peripherals in the family and can be combined as needed since they don’t typically overload the system.

The chips are built around a 16-MHz, 16-bit MSP430 core. Incorporated are 1 kB of FRAM and 512 bytes of SRAM. There’s also a 2-kB ROM that’s utilized by the collection of functions. This frees up FRAM space for additional application code.

The chips work with the usual development tools for the MSP430, including TI’s Code Composer Studio (CCS). The MSP-EXP430FR2433 LaunchPad kit (Fig. 2) is available and supports TI’s BoosterPack plug-ins.